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Background: The authors report the prospective evaluation of reduced dose alkylator chemotherapy combined with radiotherapy for European Pediatric Soft Tissue Sarcoma Study Group (EpSSG) standard risk nonalveolar rhabdomyosarcoma (NA-RMS)., Patients and Methods: Localized node negative Intergroup Rhabdomyosarcoma Study (IRS) II/III NA-RMS at favorable sites (subgroup C), <25 years old, received five cycles of ifosfamide, vincristine, and dactinomycin (IVA) chemotherapy (30 g/m 2 ifosfamide) and four cycles of vincristine and dactinomycin (if receiving radiotherapy), or nine cycles of IVA (54 g/m 2 ifosfamide) ± radiotherapy. Delayed primary tumor excision was considered for IRS III tumors. The primary end points were event-free survival (EFS) and overall survival (OS)., Results: From October 2005 to December 2016, 359 evaluable patients were recruited: orbit, 164 (45.7%); head and neck nonparameningeal, 77 (21.4%); and genitourinary non-bladder/prostate, 118 (32.9%). EFS and OS were 77.4% (95% confidence interval [CI], 72.5-81.6) and 93.5% (95% CI, 90.1-95.8), respectively. Lower dose alkylator chemotherapy and radiotherapy achieved 5-year OS of 93.7% but the difference with higher dose alkylator chemotherapy +/- radiotherapy was not significant (p = 0.8003). Adjuvant radiotherapy improved EFS with 5-year estimates of 84.7% versus 65.2% for nonirradiated (p < .0001), but not OS (p = .9298). Omitting radiotherapy for orbital tumors reduced OS (5-year was 87.1% vs. 97.3% for irradiated, p = .0257). Following R0 resection (n = 60), radiotherapy did not significantly improve EFS or OS., Conclusions: Radiotherapy for local tumor control allows for reduction of cumulative dose of alkylators in EpSSG standard risk subgroup C RMS patients. The omission of radiotherapy did not affect OS in all patients except those with orbital RMS and was associated with inferior EFS., (© 2024 The Author(s). Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society.)

Rhabdomyosarcoma (RMS) represents one of the most lethal soft-tissue sarcomas in children. The toxic trace element arsenic has been reported to function as a radiosensitizer in sarcomas. To investigate the role of arsenic sulfide (As 4 S 4 ) in enhancing radiation sensitization in RMS, this study was conducted to elucidate its underlying mechanism in radiotherapy. The combination of As 4 S 4 and radiotherapy showed significant inhibition in RMS cells, as demonstrated by the cell counting kit-8 (CCK-8) assay and flow cytometry. Subsequently, we demonstrated for the first time that As 4 S 4 , as well as the knockdown of NFATc3 led to double-strand break (DSB) through increased expression of RAG1. In vivo experiment confirmed that co-treatment efficiently inhibited RMS growth. Furthermore, survival analysis of a clinical cohort consisting of 59 patients revealed a correlation between NFATc3 and RAG1 expression and overall survival (OS). Cox regression analysis also confirmed the independent prognostic significance of NFATc3 and RAG1.Taken together, As 4 S 4 enhances radiosensitivity in RMS via activating NFATc3-RAG1 mediated DSB. NFATc3 and RAG1 are potential therapeutic targets. As 4 S 4 will hopefully serve as a prospective radio-sensitizing agent for RMS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Despite a multimodal approach including surgery, chemo- and radiotherapy, the 5-year event-free survival rate for rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in childhood, remains very poor for metastatic patients, mainly due to the selection and proliferation of tumour cells driving resistance mechanisms. Personalised medicine-based protocols using new drugs or targeted therapies in combination with conventional treatments have the potential to enhance the therapeutic effects, while minimizing damage to healthy tissues in a wide range of human malignancies, with several clinical trials being started. In this study, we analysed, for the first time, the antitumour activity of SFX-01, a complex of synthetic d, l-sulforaphane stabilised in alpha-cyclodextrin (Evgen Pharma plc, UK), used as single agent and in combination with irradiation, in four preclinical models of alveolar and embryonal RMS. Indeed, SFX-01 has shown promise in preclinical studies for its ability to modulate cellular pathways involved in inflammation and oxidative stress that are essential to be controlled in cancer treatment., Methods: RH30, RH4 (alveolar RMS), RD and JR1 (embryonal RMS) cell lines as well as mouse xenograft models of RMS were used to evaluate the biological and molecular effects induced by SFX-01 treatment. Flow cytometry and the modulation of key markers analysed by q-PCR and Western blot were used to assess cell proliferation, apoptosis, autophagy and production of intracellular reactive oxygen species (ROS) in RMS cells exposed to SFX-01. The ability to migrate and invade was also investigated with specific assays. The possible synergistic effects between SFX-01 and ionising radiation (IR) was studied in both the in vitro and in vivo studies. Student's t-test or two-way ANOVA were used to test the statistical significance of two or more comparisons, respectively., Results: SFX-01 treatment exhibited cytostatic and cytotoxic effects, mediated by G2 cell cycle arrest, apoptosis induction and suppression of autophagy. Moreover, SFX-01 was able to inhibit the formation and the proliferation of 3D tumorspheres as monotherapy and in combination with IR. Finally, SFX-01, when orally administered as single agent, displayed a pattern of efficacy at reducing the growth of tumour masses in RMS xenograft mouse models; when combined with a radiotherapy regime, it was observed to act synergistically, resulting in a more positive outcome than would be expected by adding each exposure alone., Conclusions: In summary, our results provide evidence for the antitumour properties of SFX-01 in preclinical models of RMS tumours, both as a standalone treatment and in combination with irradiation. These forthcoming findings are crucial for deeper investigations of SFX-01 molecular mechanisms against RMS and for setting up clinical trials in RMS patients in order to use the SFX-01/IR co-treatment as a promising therapeutic approach, particularly in the clinical management of aggressive RMS disease., (© 2024. The Author(s).)

Rhabdomyosarcoma (RMS) is among the most common pediatric solid malignancies. Fusion-negative, embryonal RMS is the predominant histology among prostate and bladder lesions. Management strategies depend on the clinical stage and risk group. Although the optimal strategy continues to evolve, the field has transitioned from radical upfront resection to organ preservation strategies with multi-modal therapy, including chemotherapy, radiation, and surgery. Survivors frequently develop late complications, including impaired fertility and sexual function, bladder dysfunction, and secondary malignancies. Our case describes an 11-year-old male who developed a radiation-induced prostatic sarcoma. We present a novel surgical technique and highlight the importance of multidisciplinary care., Competing Interests: Declaration of Competing Interest None of the authors have conflicts of interest relevant to this article to disclose. All authors made substantial contributions to the manuscript and agreed to submit this manuscript for publication., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Approximately one third of children with rhabdomyosarcoma relapse or have refractory disease. Treatment approaches include a combination of systemic therapies and local therapies, directed at tumour site(s). This review was conducted to evaluate the effectiveness and safety of the combination of surgery and brachytherapy as local therapy for treating children and young people with relapsed/refractory rhabdomyosarcoma. This review identified studies based on a previous systematic review looking at the treatments for children and young people under 18 years old with relapsed/refractory rhabdomyosarcoma. Studies conducted after 2000 were included. Survival outcomes, relapse rates, adverse events and functional outcomes were extracted. From 16,965 records identified in the baseline systematic review, 205 included the words 'AMORE' or 'brachytherapy', and were screened for eligibility in this substudy. Thirteen studies met the inclusion criteria for Local-REFoRMS, including over 55 relapsed and refractory rhabdomyosarcoma patients. Most studies were retrospective cohort studies conducted within Europe. Most patients had embryonal disease within the head and neck or bladder/prostate regions, and received local therapy for first relapse. Approximately one quarter of patients relapsed following surgery and brachytherapy, with local relapses occurring more than metastatic relapse. Adverse events and functional outcomes were infrequently reported, but related to the site of surgery and brachytherapy. Study quality was limited by inconsistent reporting and potential selection bias. Outcomes following surgery and brachytherapy for a selected group of relapsed and refractory rhabdomyosarcoma show reasonable benefits, but reporting was often unclear and based on small sample sizes., (© 2024 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background and Purpose: The purpose of this study was to address the lack of published data on the use of brachytherapy in pediatric rhabdomyosarcoma by describing current practice as starting point to develop consensus guidelines., Materials and Methods: An international expert panel on the treatment of pediatric rhabdomyosarcoma comprising 24 (pediatric) radiation oncologists, brachytherapists and pediatric surgeons met for a Brachytherapy Workshop hosted by the European paediatric Soft tissue Sarcoma Study Group (EpSSG). The panel's clinical experience, the results of a previously distributed questionnaire, and a review of the literature were presented., Results: The survey indicated the most common use of brachytherapy to be in combination with tumor resection, followed by brachytherapy as sole local therapy modality. HDR was increasingly deployed in pediatric practice, especially for genitourinary sites. Brachytherapy planning was mostly by 3D imaging based on CT. Recommendations for patient selection, treatment requirements, implant technique, delineation, dose prescription, dose reporting and clinical management were defined., Conclusions: Consensus guidelines for the use of brachytherapy in pediatric rhabdomyosarcoma have been developed through multicenter collaboration establishing the basis for future work. These have been adopted for the open EpSSG overarching study for children and adults with Frontline and Relapsed RhabdoMyoSarcoma (FaR-RMS)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflicts of interest Dr. Mark N. Gaze is supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre and by the Radiation Research Unit at the Cancer Research UK City of London Centre Award [C7893/A28990]. Prof. Dr. Peter Hoskin is supported by the NIHR Manchester Biomedical Centre. Dr. Henry C. Mandeville is supported by the National Institute for Health Research Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Radiation myelitis (RM) is a rare complication of radiation therapy (RT). The Pediatric Normal Tissue Effects in the Clinic spinal cord task force aimed to identify RT dose effects and assess risk factors for RM in children. Through systematic review, we analyzed RT dose, fraction size, latency between completion of RT and toxicity, chemotherapy use, age when irradiated, and sex., Methods and Materials: We conducted literature searches of peer-reviewed manuscripts published from 1964 to June 2017 evaluating RM among children. Normality of variables was assessed with Kolmogorov-Smirnov or Shapiro-Wilk tests. Spearman's rank correlation coefficients were used to test correlations between RT dose/fraction size and latency between RT and development of toxicity., Results: Of 1329 identified and screened reports, 144 reports were fully reviewed and determined to have adequate data for analysis; 16 of these reports had a total of 33 cases of RM with a median age of 13 years (range, 0.2-18) at the time of RT. The most common primary tumor histologies were rhabdomyosarcoma (n = 9), medulloblastoma (n = 5), and Hodgkin lymphoma (n = 2); the most common chemotherapy agents given were vincristine (n = 15), intrathecal methotrexate (n = 12), and intrathecal cytarabine (n = 10). The median RT dose and fraction size were 40 Gy (range, 24-57.4 Gy) and 1.8 Gy (range, 1.3-2.6 Gy), respectively. RT dose resulting in RM in patients who also received chemotherapy was lower than in those not receiving chemotherapy (mean 39.6 vs 49.7 Gy; P = .04). There was no association of age with RT dose. The median latency period was 7 months (range, 1-29). Higher RT dose was correlated with longer latency periods (P = .03) to RM whereas sex, age, fraction size, and chemotherapy use were not. Two of 17 patients with adequate follow-up recovered from RM; unfortunately, it was fatal in 6 of 15 evaluable patients. Complication probability modeling was not possible because of the rarity of events., Conclusions: This report demonstrates a relatively short latency from RT (with or without chemotherapy) to RM and a wide range of doses (including fraction sizes) associated with RM. No apparent association with age at the time of RT could be discerned. Chemotherapy appears to reduce spinal cord tolerance. Recovery from RM is rare, and it is often fatal., (Copyright © 2024 Elsevier Inc. All rights reserved.)

BACKGROUND Sinonasal rhabdomyosarcoma (RMS) is a rare malignancy in children and adolescents. It is aggressive and locally invasive, and can require local postoperative radiotherapy. This report presents the case of a 16-year-old girl with a sinonasal-cutaneous fistula following excision and radiotherapy for rhabdomyosarcoma, which required reconstructive surgery using an expanded forehead flap. CASE REPORT We report the case of a16-year-old girl who was referred to our clinic with sinonasal-cutaneous fistula. Prior to presentation at our department, she presented with bilateral intermittent nasal congestion 3 years ago. At a local hospital, orbital computed tomography and nasal endoscopic biopsy revealed an embryonal rhabdomyosarcoma (ERMS). One month later, skull base tumor resection, nasal cavity and sinus tumor resection, and low-temperature plasma ablation were performed at a local hospital. Two weeks after the operation, the patient received intensity-modulated radiation therapy for a total of 50 Gy. Chemotherapy started 15 days after radiotherapy, using a vincristine, dactinomycin, and cyclophosphamide (VAC) regimen. Approximately 1 month later, an ulcer appeared at the nasal root and the lesion gradually expanded. The patient was referred to our hospital due to the defect. Firstly, a tissue expander was implanted at the forehead for 7 months. Then, the skin around the defect was trimmed and forehead flap was separated to repair the lining and external skin. The flap survived well 1-year after the operation. CONCLUSIONS This report highlights the challenges of post-radiation reconstructive surgery and describes how an expanded forehead flap can achieve an acceptable cosmetic outcome in a patient with a sinonasal-cutaneous fistula.

Background: Adult head and neck rhabdomyosarcoma (HNRMS) is an exceptionally rare malignancy, and there is a paucity of data and research dedicated to understanding its characteristics and management in adult populations. This study aimed to assess the outcomes and identify survival predictors in adult HNRMS., Methods: We retrospectively evaluated 42 adult patients (> 16 years) with HNRMS who received radiotherapy (RT)-based treatment at our institute between 2008 and 2022. We analysed the clinical characteristics and prognosis of these patients, including the locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and overall survival (OS), using the Kaplan-Meier method. The chi-square and Fisher's exact tests were used to analyse differences between groups for dichotomous and categorical variables, respectively. Survival rates were calculated using the Kaplan-Meier method. Prognostic variables were assessed through univariate Cox analyses., Results: The median patient age was 28 years (range, 16-82 years). Alveolar RMS was the most common histological type, observed in 21 patients (50.0%), followed by embryonal in 16 patients (38.1%). The anatomic sites of origin were orbital in one (2.4%), parameningeal in 26 (61.9%), and non-orbital/non-parameningeal in 15 (35.7%) patients. Nineteen patients (45.2%) had regional lymph node metastasis, and five patients (11.9%) presented with distant metastatic disease. Distant metastasis (n = 17) was the primary cause of treatment failure. At a median follow-up of 47.0 months, the 5-year LRFS, PFS, and OS rates were 69.0%, 39.7%, and 41.0%, respectively. Univariate analysis revealed that tumour size, lymph node involvement, and the local treatment pattern (surgery and RT vs. RT alone) were significant predictors of survival., Conclusions: The main failure pattern in patients with HNRMS receiving RT-based treatment was distant metastasis. Tumour size > 5 cm and lymph node involvement were predictors of worse LRFS. Multimodality local treatment, combining surgery and RT, is effective and provides survival benefits., (© 2024. The Author(s).)

Competing Interests: Competing interests: None declared.

Background: Treatment for parameningeal rhabdomyosarcoma (PM-RMS) has been a challenge since local control is difficult. The goal of this study was to analyse the impact of different local treatment approaches on childhood PM-RMS patients and help dispel the doubt that whether secondary radical surgery (SRS) should be encouraged in the management of PM-RMS., Methods: A total of 17 children with PM-RMS who received unified systemic chemotherapy and individualized local therapy such as radiotherapy (RT) and/or SRS were included in this retrospective study. The overall survival (OS) and event free survival (EFS) were compared between groups adopting different local strategies., Results: The 3-year OS and EFS of our PM-RMS patients was 75.5% and 56.5% respectively. The OS and EFS of patients who received SRS were both significantly lower than that of the non-SRS group (3-year OS: 50.0% vs 90.0%, P = .031; 3-year EFS: 33.3% vs 60.6%, P = .020). The OS and EFS of the patients who received RT was higher than that of the patients of the non-RT group (3-year OS: 85.6% vs 0%, P = .001; 3-year EFS: 64.0% vs 0%, P = .011)., Conclusion: This study illustrates that SRS was associated with poor prognosis of PM-RMS and should not be routinely performed. Optimized RT strategies along with more intensive chemotherapy may be alternative options to improve the survival of patients with PM-RMS. Multi-center, large sample and prospective studies are needed to further validate these findings., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Parameningeal location of rhabdomyosarcoma (PM RMS) is known to be an unfavorable prognostic factor. Scarce data are available on radiotherapy (RT) concepts with regard to outcome., Methods: Treatment and outcome of 395 children with PM RMS registered within two Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1995-2021) were evaluated., Results: Patients were IRS group II (n = 15) and III (n = 380) and received systemic treatment according to the enrolled protocols: I2VA (n = 172), VAIA/CEVAIE (n = 223). Delayed resection was performed in 88/395 (22%) patients, and RT was additionally given in 79/88 (90%) resected patients. RT was the predominant local treatment in 355/395 (90%) patients: hyperfractionated accelerated photon (HART; n = 77), conventionally fractionated photon (n = 91) or proton beam (n = 126), brachytherapy (n = 4), heavy ions (n = 1), not available (n = 56). In the subgroup of RT as only local treatment (n = 278), no intracranial tumor extension and complete remission at end of treatment were significant positive prognostic factors. No significant difference on tumor outcome was seen between different radiotherapy concepts. Long-term toxicity with mostly endocrinological and visual deficiencies was reported in 161/279 (58%) surviving patients with a lower trend after proton beam RT (48%) when compared to HART or conventionally fractionated photon RT (71% and 72%, respectively). Ten-year event-free and overall survival in the overall group were 62% (±5, 95% confidence interval [CI]) and 67% (±5, 95% CI); in the RT-only group 67% (±6, 95% CI) and 71% (±6, 95% CI), respectively., Conclusion: CWS data confirm the recent RT concept in PM RMS. Long-term sequelae as endocrinological and visual deficiencies need to be addressed., (© 2023 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Background: Para-testicular Rhabdomyosarcoma (PT-RMS) has a favorable treatment outcome adopting multidisciplinary management; resection, namely high inguinal orchiectomy ± retro-peritoneal lymph node dissection (RPLND) followed by standard or intensive chemotherapy ± adjuvant radiation therapy., Patients and Methods: This is a retrospective study including all patients with pathologically proven PT-RMS, presented to the National Cancer Institute, Cairo University, during the period from 2005 to 2020. Endpoints included overall survival, disease free survival and patterns of failure of different treatment modalities., Results: Forty one patients were identified. Median age in our cohort was 15 years (range: 2-54 years). After a median follow up of 26 months (range, 3-75 months) ,two and five years OS were 100% and 91.7% respectively and median survival was not reached. Patients who underwent retro-peritoneal nodal dissection had a 5-year DFS rate of 100% versus 73% for those who received radiation to para-aortic nodes (p = 0.185). Limitations include retrospective nature and deviation from COG protocol., Conclusions: This study shows promising results suggesting that less aggressive local treatment modalities including radiation to para-aortic chain could be an option in PT-RMS, given the excellent results of this subtype. However further validation in a prospective study is warranted.

Background: The four different local therapy strategies used for head and neck rhabdomyosarcoma (HNRMS) include proton therapy (PT), photon therapy (RT), surgery with radiotherapy (Paris-method), and surgery with brachytherapy (AMORE). Local control and survival is comparable; however, the impact of these different treatments on facial deformation is still poorly understood. This study aims to quantify facial deformation and investigates the differences in facial deformation between treatment modalities., Methods: Across four European and North American institutions, HNRMS survivors treated between 1990 and 2017, more than 2 years post treatment, had a 3D photograph taken. Using dense surface modeling, we computed facial signatures for each survivor to show facial deformation relative to 35 age-sex-ethnicity-matched controls. Additionally, we computed individual facial asymmetry., Findings: A total of 173 HNRMS survivors were included, survivors showed significantly reduced facial growth (p < .001) compared to healthy controls. Partitioned by tumor site, there was reduced facial growth in survivors with nonparameningeal primaries (p = .002), and parameningeal primaries (p ≤.001), but not for orbital primaries (p = .080) All patients were significantly more asymmetric than healthy controls, independent of treatment modality (p ≤ .001). There was significantly more facial deformation in orbital patients when comparing RT to AMORE (p = .046). In survivors with a parameningeal tumor, there was significantly less facial deformation in PT when compared to RT (p = .009) and Paris-method (p = .007)., Interpretation: When selecting optimal treatment, musculoskeletal facial outcomes are an expected difference between treatment options. These anticipated differences are currently based on clinicians' bias, expertise, and experience. These data supplement clinician judgment with an objective analysis highlighting the impact of patient age and tumor site between existing treatment options., (© 2023 The Authors. Pediatric Blood & Cancer published by Wiley Periodicals LLC.)

Purpose: In pediatric bladder/prostate-rhabdomyosarcoma, the rate of bladder preservation after neoadjuvant chemotherapy is high, with an excellent oncological outcome. Information about functional urological long-term outcomes is rare., Methods: Data of all patients who had undergone bladder-preserving surgery with or without brachytherapy at our institution between 2009 and 2020 were analyzed retrospectively. Detailed urological function was assessed focusing on age-related continence, bladder capacity and urodynamic findings., Results: We identified 40 patients, median age at surgery of 27 months (range 9-191), and 32 patients additionally received postoperative high-dose-rate brachytherapy. The median follow-up was 32.5 months (range 6-125). The bladder capacity increased from median 66.7% (21.1-180) of expected bladder capacity related to age 3 months after surgery to 87.4% (58.1-181.8) 9 months after surgery. In the group of aged > 6-year-old, continence was 94% (83% with brachytherapy, 100% without brachytherapy). Erectile function was normal in 92% (90% with brachytherapy, 100% without brachytherapy). Bladder capacity was more than 65% expected bladder capacity related to age in 70% (60% with brachytherapy, 86% without brachytherapy). 65% of all patients need neither anticholinergic drugs nor low-dose antibiotics (63% with brachytherapy, 71% without brachytherapy)., Conclusions: Bladder preservation with good functional outcome can be achieved in localized bladder/prostate-rhabdomyosarcoma. In selected cases, supportive brachytherapy additionally contributes to an improvement in the oncological outcome with calculable risks for bladder and erectile function. Careful urological aftercare should be a fixed priority after oncological follow-ups., (© 2022. The Author(s).)

Background: Posttherapy imaging studies can provide reassurance or induce anxiety regarding risk of recurrence for patients and their families. In some cases, it is difficult to determine if imaging findings represent posttreatment changes or residual disease. Equivocal radiographic findings can occur due to therapy-related inflammation or residual, inactive soft tissue masses, but it is unknown if such findings indicate an increased likelihood of local recurrence. The aim of this study was to assess the value of initial posttherapy scans for predicting local relapse in patients with Ewing sarcoma (EWS) or rhabdomyosarcoma (RMS) who received radiotherapy (RT) for local control. These findings are critical to inform clinicians' surveillance recommendations and ability to accurately counsel patients and their families., Procedure: The primary endpoint was time to local progression (LP). Patients were classified as having posttherapy scans that were "positive" (residual disease within the RT field), "negative" (no evidence of residual disease within the RT field), or "equivocal" (no determination could be made). The value of initial posttreatment scans for predicting LP was assessed using positive predictive value (PPV) and negative predictive value (NPV)., Results: Negative imaging findings (n = 51) had an NPV of 88%, and positive imaging findings (n = 1) had a PPV of 100%. When equivocal findings (n = 16) were categorized with negative results (i.e., positive vs. equivocal/negative), the NPV was 90%. When equivocal findings were categorized with positive results (equivocal/positive vs. negative), the PPV was 12%., Conclusion: Equivocal findings within the RT field on end-of-therapy imaging studies indicate no higher risk of local recurrence than negative findings. These results may contribute to appropriate surveillance schedules and accurate counseling of patients with RMS and EWS who have received RT for local control., (© 2023 Wiley Periodicals LLC.)

Background: Persisting residual masses at treatment completion are known in rhabdomyosarcoma (RMS) treated with definitive radiotherapy (RT) to the primary site, but their prognostic significance is uncertain. Tumor response as assessed by anatomic imaging is not prognostic and studies based on 18 F-FDG-PET response are limited. We report the prognostic significance of persistent FDG-avidity in residual masses, assessed 3-month postdefinitive RT, in pediatric RMS., Materials and Methods: Children 15 years old or below with Group III/IV RMS who received only definitive radiotherapy for local control from June 2013 to December 2018, and had 18 F-FDG-PET CT at 3 months post-RT were retrospectively analyzed for outcomes and other prognostic factors., Results: Sixty-three children were eligible (Group III-55, Group IV-8). 18 F-FDG-PET CT scan done 3 months postradiotherapy showed FDG-avid residual masses in 10 patients (15.9%), anatomic residual in 24 (38.1%), and no anatomic/FDG-avid residual in 29(46.0%). At a median follow-up of 38 months (interquartile range, 24 to 55 mo), 3-year EFS of patients with FDG-avid residual masses was 40.0% (95% CI: 18.7% to 85.5%) versus the rest of the cohort, which was 71.9% (95% CI: 59.8% to 86.5%) ( P =0.008). Three-year OS of patients with FDG-avid residual masses was 50.8% (95% CI: 25.7% to 100.0%) versus the rest of the cohort, which was 77.0% (95% CI: 65.1% to 91.0%) ( P =0.037). Presence of FDG-avid residual disease persisting post-RT affected both EFS [HR-3.34 (95% CI: 1.29 to 8.68) ( P =0.013)] and OS [HR-3.20 (95% CI: 1.01 to 10.12) ( P =0.048)] on univariate analysis and this significance was retained for EFS in multivariate analysis [HR-3.52 (95% CI: 1.33 to 9.30) ( P =0.011)]., Conclusions: Persistent metabolic activity in residual disease post-chemoradiotherapy in RMS may portend a poorer prognosis with an increased risk of relapse. This subset of high-risk patients needs to be identified, and further trials are warranted to develop strategies to improve their outcomes., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To characterize on-treatment changes in GTV morphology in children with parameningeal rhabdomyosarcoma receiving upfront proton therapy with concurrent chemotherapy and thereby provide guidance on the timing of on-treatment imaging and adaptive replanning., Methods and Materials: GTV was delineated on 86 simulation and weekly MR images of 15 prospectively enrolled patients (aged 1-21 years). Temporal changes from baseline in volume and surface (95% Hausdorff distance) were analyzed in relation to the need for plan verification and the resultant doses with hypothetical no treatment adaptation., Results: The median time was 6 days from the initiation of chemotherapy to CT+MR simulation and 15 days from the simulation to the start of radiotherapy. All but 1 patient showed a continuous decrease in GTV (0.16-1.52%/day) after simulation. At 3 weeks from simulation, 10 of 15 patients exhibited a significant reduction in volume (median, 20%; range, 6-29%). Without replanning, these changes could lead to a reduction in CTV V95 by 7-14% (n = 2) and/or an increase in D0.01 cc/Dmean of adjacent organs at risk by 6-21% of the prescribed target dose (n = 7). Significant dosimetric consequences occurred in cases with (1) a considerable weight gain, (2) shrinkage of the skin surface, or (3) tumor regression in the oral or nasal cavity and sinus that altered air-tissue components in the beam path. The subsequent GTV and dosimetry after 3 weeks from simulation (4 weeks from chemotherapy initiation) demonstrated a relatively stable trend., Conclusions: On-treatment imaging at 3 weeks after simulation is recommended, if the simulation is performed at 1 week after the initiation of chemotherapy, to detect significant anatomic changes that could result in >5% deviation from planned target coverage and/or organ doses in pediatric patients with parameningeal rhabdomyosarcoma receiving early proton therapy., (Copyright © 2023 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Objective: This study aimed to evaluate and conduct a meta-analysis on the efficacy and safety of proton beam therapy (PBT) for rhabdomyosarcoma (RMS)., Methods: We searched for articles using PubMed, Embase, Cochrane Library, and Web of Science databases from their inception to December 22, 2022. Two researchers independently screened literature and extracted data. Statistical analyses were performed using STATA version 14.0., Results: We got 675 candidate articles, of which 11 studies were included in our study according to the inclusion and exclusion criteria. Of the 544 RMS patients who received PBT. The local control (LC) rate at 1, 2, 3, 4, and 5 years were 96% (95% confidence interval (CI) 0.91-1.01), 93% (95% CI 0.86-1.00), 78% (95% CI 0.71-0.85), 85% (95% CI 0.78-0.92), and 84% (95% CI 0.74-0.95), respectively. The progression-free survival (PFS) rate at 1, 2, 3, 4, and 5 years were 82% (95% CI 0.72-0.92), 73% (95% CI 0.61-0.84), 63% (95% CI 0.47-0.79), 64% (95% CI 0.54-0.74), and 76% (95% CI 0.59-0.94), respectively. The overall survival (OS) rate at 1, 2, 3, 4, and 5 years were 93% (95% CI 0.86-1.00), 85% (95% CI 0.76-0.95), 80% (95% CI 0.63-0.96), 71% (95% CI 0.62-0.80), and 82% (95% CI 0.71-0.94), respectively. Acute and late toxicities were mainly grades 1 to 2 in all studies., Conclusion: As an advantageous RT technique, PBT is an emerging option for patients with RMS, particularly children and adolescents patients. The data showed that PBT is a feasible, safe, and effective modality for RMS, showing promising LC, OS, PFS, and lower acute and late toxicities. PROSPERO registration number: CRD42022329154., (© 2023. The Author(s).)

In fusion-negative rhabdomyosarcoma (FN-RMS), a pediatric malignancy with skeletal muscle characteristics, >90% of high-risk patients have mutations that activate the RAS/MEK signaling pathway. We recently discovered that SNAI2, in addition to blocking myogenic differentiation downstream of MEK signaling in FN-RMS, represses proapoptotic BIM expression to protect RMS tumors from ionizing radiation (IR). As clinically relevant concentrations of the MEK inhibitor trametinib elicit poor responses in preclinical xenograft models, we investigated the utility of low-dose trametinib in combination with IR for the treatment of RAS-mutant FN-RMS. We hypothesized that trametinib would sensitize FN-RMS to IR through its downregulation of SNAI2 expression. While we observed little to no difference in myogenic differentiation or cell survival with trametinib treatment alone, robust differentiation and reduced survival were observed after IR. In addition, IR-induced apoptosis was significantly increased in FN-RMS cells treated concurrently with trametinib, as was increased BIM expression. SNAI2's role in these processes was established using overexpression rescue experiments, where overexpression of SNAI2 prevented IR-induced myogenic differentiation and apoptosis. Moreover, combining MEK inhibitor with IR resulted in complete tumor regression and a 2- to 4-week delay in event-free survival (EFS) in preclinical xenograft and patient-derived xenograft models. Our findings demonstrate that the combination of MEK inhibition and IR results in robust differentiation and apoptosis, due to the reduction of SNAI2, which leads to extended EFS in FN-RMS. SNAI2 thus is a potential biomarker of IR insensitivity and target for future therapies to sensitize aggressive sarcomas to IR., (©2022 American Association for Cancer Research.)

Background: The prognosis for patients with metastatic rhabdomyosarcoma (RMS) remains largely unsatisfactory despite the adoption of intensive multimodal therapy. To assess the role of different treatments adopted over the years, we retrospectively analyzed a cohort of patients &lt;21 years old with metastatic RMS, treated from 1990 to 2020 at a referral center for pediatric sarcomas., Methods: Patients were treated using a multimodal approach that included surgery, radiotherapy, and chemotherapy (both high-dose chemotherapy and maintenance therapy in some cases). The type of radiotherapy administered was categorized as radical (to all sites of disease); partial (to at least one, but not all sites of disease); or none. A landmark analysis was used to examine the impact of radiotherapy on survival, that is, patients who had an event before day 221 were excluded from the analysis., Results: The series included 80 patients. Event-free survival (EFS) and overall survival (OS) rates at 5 years were 17.3% and 21.3%, respectively. Survival was significantly associated with radiotherapy to metastatic sites, and with the radiotherapy category. In particular, 5-year EFS and OS rates were 70.6% and 76.0% for patients given radical radiotherapy, and 4.8% and 10.7%, respectively, for those given partial radiotherapy or none. Using the Cox multivariable analysis, OS correlated significantly with radiotherapy category., Conclusions: While confirming the poor overall outcome of patients with metastatic RMS, this study identified radiotherapy-when given to all sites of disease (including metastases)-as the main variable influencing survival., (© 2022 Wiley Periodicals LLC.)

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood and adolescence that includes FP-RMS, harboring the fusion oncoprotein PAX3/7-FOXO1 and FN-RMS, often mutant in the RAS pathway. Risk stratifications of RMS patients determine different prognostic groups and related therapeutic treatment. Current multimodal therapeutic strategies involve surgery, chemotherapy (CHT) and radiotherapy (RT), but despite the deeper knowledge of response mechanisms underpinning CHT treatment and the technological improvements that characterize RT, local failures and recurrence frequently occur. This review sums up the RMS classification and the management of RMS patients, with special attention to RT treatment and possible radiosensitizing strategies for RMS tumors. Indeed, RMS radioresistance is a clinical problem and further studies aimed at dissecting radioresistant molecular mechanisms are needed to identify specific targets to hit, thus improving RT-induced cytotoxicity.

Background: Conservative surgery (CS) brachytherapy (BT) techniques for local therapy in bladder-prostate rhabdomyosarcoma (BP-RMS) seek to retain organ function. We report bladder function after high-dose rate (HDR) BT combined with targeted CS for any vesical component of BP-RMS., Procedure: Prospective cohort of all BP-RMS patients between 2014 and 2019 receiving HDR-BT (iridium-192, 27.5 Gy in five fractions) with/without percutaneous endoscopic polypectomy (PEP) or partial cystectomy (PC). Functional assessment included frequency-volume chart, voided volumes, post-void residual, flow studies, continence status and ultrasound scanning; abnormalities triggered video urodynamics., Results: Thirteen patients (10 male), aged 9 months to 4 years (median 23 months), presented with localised fusion-negative embryonal BP-RMS measuring 23-140 mm (median 43 mm) in cranio-caudal extent. After induction chemotherapy, local treatment consisted of PC+BT in three, PEP+BT in four and BT alone in six. At a median 3.5 years (range 21 months to 7 years) follow-up, all were alive without relapse. At a median age of 6 years (4-9 years), the median bladder capacity was 86% (47%-144%) of that expected for age, including 75% (74%-114%) after PC. Radiation dose to the bladder was associated with urinary urgency, but not bladder capacity or nocturnal enuresis. Complications occurred in two: one urethral stricture and one vesical decompensation in a patient with pre-existing high-grade vesico-ureteric reflux (VUR). The remaining patients were dry by day; five with anticholinergic medication for urinary urgency. Three patients are enuretic., Conclusions: Day-time dryness at a median 3.5 years after CS-HDR-BT was achieved in 92%, with 85% voiding urethrally, and 62% attaining day-and-night continence aged 4-9 years. We report reduced open surgery with minimally invasive percutaneous surgery, with HDR-BT or BT alone being suitable for many., (© 2022 Wiley Periodicals LLC.)

Background: Outcome of children with bladder-prostate rhabdomyosarcoma (RMS) has improved with multimodal therapies, including surgery and/or radiotherapy for local treatment. Our aim was to report long-term urological complications after a conservative approach combining conservative surgery and brachytherapy., Patients and Methods: Eighty-six patients, free of disease, were retrospectively reviewed. Symptoms related to urinary tract obstruction, incontinence, infection, and lithiasis were reported and graded according to the Common Terminology Criteria for Adverse Events (CTCAE) classification. Only symptomatic patients underwent urodynamic studies. Risk factors for complications were analyzed., Results: There were 76 males and 10 females. The median follow-up was 6.3 years (18 months to 24 years). Complications occurred after a median follow-up of 5 years (0-21). Twenty-two patients (26%) had long-term urological complications. Urinary tract obstruction was found in 15 patients (17%) and urinary incontinence in 14 patients (16%). Recurrent urinary tract infection occurred in four patients and urinary lithiasis in four (5%). The underlying physiopathology included bladder dysfunction in 15 patients (17%), urethral stenosis in six (7%), and ureterovesical junction stenosis in five (6%). On univariate analysis, posterior bladder wall dissection (p = .001), bladder neck trigone dissection (p = .010), and partial prostatectomy (p = .023) were significantly associated with an increased risk of bladder dysfunction; on multivariate analysis, only age ≤2 years (p = .028) at operation and posterior bladder wall dissection (p = .006) were found to be significant., Conclusion: The conservative surgical approach combined with brachytherapy for bladder-prostate RMS leads to long-term urological complications in 26% of survivors. Optimizing brachytherapy doses for young children and establishing a clear and long-term follow-up protocol could help to reduce these complications., (© 2021 Wiley Periodicals LLC.)

Purpose: Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers., Methods and Materials: We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy., Results: We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy., Conclusions: This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: A novel concept for an organ-preserving treatment of pediatric urogenital and perianal rhabdomyosarcoma includes high dose rate brachytherapy following surgical tumor resection. For the duration of the brachytherapy of 6 days plus 2-day recovery break the patients are not allowed to move and are kept under deep sedation, which can lead to difficult weaning from mechanical ventilation, withdrawal, delirium, and prolonged hospital stay. The aim of this study was to evaluate a protocol which includes a switch from fentanyl to ketamine 3 days prior to extubation to help ensure a rapid extubation and transfer from PICU., Methods: Patients who underwent surgical tumor resection of rhabdomyosarcoma and subsequent brachytherapy were treated according to a standardized protocol. We evaluated doses of fentanyl, midazolam and clonidine, time of extubation, length of PICU stay and occurrence of withdrawal symptoms and delirium. We compared fentanyl dose at time of extubation, duration of weaning from mechanical ventilation and time to discharge from PICU with patients after isolated severe traumatic brain injury., Results: Twentytwo patients (age 39.9 ± 29.8 months) were treated in our PICU to undergo brachytherapy. Extubation was performed 21.6 ± 13.5 h after the last brachytherapy session with an average fentanyl dose of 1.5 ± 0.5 µg/kg/h and patients were discharged from PICU 58.4 ± 30.3 h after extubation, which all is significantly lower compared to the control group (extubation after 88.0 ± 42.2 h, p < 0.001; fentanyl dose at the time of extubation 2.5 ± 0.6 µg/kg/h, p < 0.001; PICU discharge after 130.1 ± 148.4 h, p < 0.009). Withdrawal symptoms were observed in 9 patients and delirium in 13 patients., Conclusion: A standardized analgesia and sedation protocol including an opioid break, scoring systems to detect withdrawal symptoms and delirium, and tapering plans contributes to successful early extubation and discharge from PICU after long-term deep sedation., Competing Interests: Declaration of Competing Interest On behalf of all authors, the corresponding author states that there are no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Purpose: Interstitial brachytherapy is indicated as part of a conservative strategy for children with bladder and/or prostate rhabdomyosarcoma (RMS), providing high local control probability with acceptable functional results. Vaginal and/or rectal complications were however reported, due to the close proximity to the implanted volume. We investigated the dosimetric impact of a vaginal spacer in terms of rectal and vaginal doses., Methods and Patients: Medical records of 12 consecutive female patients with bladder neck RMS, median age 32 months (range: 1.3-6 years), were reviewed. Five patients were treated prior to 2017 without a vaginal spacer and seven patients treated after 2017 had their brachytherapy delivered with a vaginal spacer placed at time of implant., Results: Minimal doses delivered to the most exposed 2cm 3 , 1cm 3 , and 0.5cm 3 of the rectum were all statistically significantly lower among patients treated with a vaginal spacer, as compared to those treated without a spacer. Median rectal D2cm 3 was 22Gy EQD2 versus 38Gy EQD2 (P=0.02), D1cm 3 was 29Gy EQD2 versus 51Gy EQD2 (P=0.013), and D0.5cm 3 was 32Gy EQD2 versus 61Gy EQD2 (P=0.017), with and without the vaginal spacer, respectively. The posterior vaginal wall D0.5cm 3 dose was also significantly decreased, with median D0.5cm 3 of 92Gy EQD2 versus 54Gy EQD2 (P<0.0001), with and without the spacer, respectively. Acute tolerance was excellent in all patients, with no need for replanning and no acute complication., Conclusions: The use of vaginal spacers in brachytherapy of female pediatric patients with bladder neck RMS resulted in significantly decreased doses to the rectum and the posterior vaginal wall. Though the clinical impact of such dose reduction remains undemonstrated, routine utilization of a vaginal spacer could be a method to decrease long-term morbidity in these patients., (Copyright © 2021 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)

Background: Extremity rhabdomyosarcoma differs from other soft tissue sarcomas, being highly sensitive to chemotherapy and radiotherapy and having a high rate of metastasis to lymph nodes. Therefore, the treatment modality differs from that of other soft tissue sarcomas. The purpose of this study was to conduct a longitudinal questionnaire survey of orthopedic oncologists in charge of surgical treatment for extremity rhabdomyosarcoma in Japan to determine whether the treatment modality chosen here is in line with the international and national treatment ones., Methods: Questionnaire surveys were conducted in 2012 and 2019 to orthopedic oncologists of Japanese Orthopaedic Association and Japanese Musculoskeletal Oncology Group., Results: Responses were obtained from 80 facilities and 76 facilities, respectively. Fewer than 50% of the facilities treated one or more patients a year in both years. Many facilities first performed diagnostic biopsy, but most did not perform pretreatment re-excision. The number of facilities that provided radiotherapy in addition to surgery increased significantly from 2012 to 2019 (P = 0.028), but it was still 21% in 2019. The number of facilities performing excision and lymph node dissection was 19% in both 2012 and 2019, which was a very low result without improvement. The departments responsible for follow-up have been changed to pediatrics and orthopedic oncology in tandem (P = 0.0004)., Conclusions: Radiotherapy and pathological evaluation of lymph nodes are important for improving the prognosis of patients with extremity rhabdomyosarcoma. It is necessary to continue and develop more efficient educational activities on the appropriate medical treatment modalities for extremity RMS., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A third of children with cancer receive radiotherapy as part of their initial treatment, which represents 800 paediatric irradiations per year in France carried out in 15 specialized centres approved on the recommendations of the French national cancer institute in decreasing order of frequency, the types of cancer that require irradiation are: brain tumours, neuroblastomas, Ewing's sarcomas, Hodgkin's lymphomas, soft tissue sarcomas including rhabdomyosarcomas, and nephroblastomas. The treatment guidelines follow the recommendations of the French society for childhood cancers (SFCE) or the French and European prospective protocols. The therapeutic indications, the technical and/and ballistic choices of complex cases are frequently discussed during bimonthly paediatric radiotherapy technical web-conferences. All cancers combined, overall survival being 80%, long-term toxicity logically becomes an important concern, making the preparation of treatments complex. The irradiation methods include all the techniques currently available: 3D conformational irradiation, intensity modulation radiation therapy, irradiation under normal or hypofractionated stereotaxic conditions, brachytherapy and proton therapy. We present the update of the recommendations of the French society for radiation oncology on the indications, the technical methods of realization and the organisation and the specificities of paediatric radiation oncology., (Copyright © 2021. Published by Elsevier Masson SAS.)

Purpose: There is limited evidence to define the role of radiation therapy in children with metastatic rhabdomyosarcoma (mRMS). In the international BERNIE study, children with mRMS or non-RMS soft tissue sarcoma were randomized to receive standard chemotherapy with or without bevacizumab, with radiation therapy to all disease sites recommended after chemotherapy cycle 6. We retrospectively evaluated the impact of radiation therapy on survival in the mRMS cohort., Methods and Materials: Patients were grouped according to the radiation therapy they received: radical, partial, or none. Radical irradiation was defined as radiation therapy delivered to all disease sites, unless a site was completely surgically resected. Partial irradiation was defined as radiation therapy to ≥1, but not all, disease sites. Landmark analysis excluded patients with an event before day 221. Overall survival (OS) and event-free survival (EFS) were modeled using Cox proportional hazards models., Results: Of 102 patients with mRMS, 97 were included in the analysis for OS and 85 for EFS. Overall, 27 patients received radical irradiation, 46 partial irradiation, and 24 no irradiation. EFS was not significantly different among patient groups after adjustment for prognostic factors (hazard ratio [HR] = 0.520; P = .054 for any vs no irradiation). Radiation therapy was associated with improved OS compared with no radiation therapy (adjusted HR = 0.249; P = .00025), with OS being greater for radical versus partial irradiation (HR = 0.245; P = .039). The 3-year OS rate was 84%, 54%, and 23% for patients receiving radical, partial, and no irradiation, respectively. Radical treatment (surgery, irradiation, or both) of the primary site improved EFS and OS compared with no treatment., Conclusions: These findings demonstrate variability in the application of radiation therapy for mRMS and support the routine use of radical treatment to the primary site. Radical irradiation to metastatic sites may further improve OS. The burden of such treatment should be balanced against prognosis; further studies are needed., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The use of curative-intent multimodality therapy with chemotherapy, surgery, and radiation results in late toxicities in almost two-thirds of patients with pediatric cancer. When pelvic radiation is used for pediatric malignancies such as rhabdomyosarcoma, lymphoma, neuroblastoma, Ewing sarcoma, and Wilms tumor, the associated late toxicities can affect many normal tissues and may include growth asymmetries, cystitis, infertility, and sexual dysfunction. We describe 4 recommendations of how to prevent or minimize late toxicities from pelvic radiation and review the literature of these pediatric late toxicities., (Copyright © 2021 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. About 25% of RMS expresses fusion oncoproteins such as PAX3/PAX7-FOXO1 (fusion-positive, FP) while fusion-negative (FN)-RMS harbors RAS mutations. Radiotherapy (RT) plays a crucial role in local control but metastatic RMS is often radio-resistant. HDAC inhibitors (HDACi) radio-sensitize different cancer cells types. Thus, we evaluated MS-275 (Entinostat), a Class I and IV HDACi, in combination with RT on RMS cells in vitro and in vivo. MS-275 reversibly hampered cell survival in vitro in FN-RMS RD (RASmut) and irreversibly in FP-RMS RH30 cell lines down-regulating cyclin A, B, and D1, up-regulating p21 and p27 and reducing ERKs activity, and c-Myc expression in RD and PI3K/Akt/mTOR activity and N-Myc expression in RH30 cells. Further, MS-275 and RT combination reduced colony formation ability of RH30 cells. In both cell lines, co-treatment increased DNA damage repair inhibition and reactive oxygen species formation, down-regulated NRF2 , SOD , CAT and GPx4 anti-oxidant genes and improved RT ability to induce G2 growth arrest. MS-275 inhibited in vivo growth of RH30 cells and completely prevented the growth of RT-unresponsive RH30 xenografts when combined with radiation. Thus, MS-275 could be considered as a radio-sensitizing agent for the treatment of intrinsically radio-resistant PAX3-FOXO1 RMS.

Background & Purpose: In infants with rhabdomyosarcoma, young age is considered an adverse prognostic factor and treatment is often attenuated to reduce side effects. Proton therapy may improve the therapeutic ratio in these patients. We report outcomes in infants with rhabdomyosarcoma treated with proton therapy., Materials & Methods: Between 2009 and 2019, 37 infants <24 months old with non-metastatic rhabdomyosarcoma received proton therapy. Local control (LC), progression-free survival (PFS), and overall survival (OS) were estimated using the Kaplan-Meier product limit. The log-rank test assessed significance between selected prognostic factors. Toxicity was graded per CTCAEv5.0., Results: Median follow-up was 5.1 years. Overall, 76% of patients had an unfavorable primary site. Median dose was 50.4GyRBE. At 5 years, LC, PFS, and OS rates were 83%, 78%, and 83%. On univariate analysis, 5-year LC and OS were inferior for favorable versus unfavorable disease sites (67% vs 89%, 67% vs 89%, respectively; p < .05) and 5-year OS was superior in stage 3 versus stage 1-2 disease (91% vs 69%; p = .05), owing to inclusion of nasal ala patients among stage 1. Of 9 recurrences, 7 were in-field, 4 occurring in infants with nasal ala primaries. Recategorizing nasal ala as an unfavorable site resulted in 100% 5-year LC and OS for favorable sites. Six infants experienced late grade 3 toxicity. None developed grade 4 or 5 late toxicity., Conclusions: Young age alone may not be an adverse prognostic factor provided infants receive local therapy similar to older children. Consideration should be given to classifying nasal ala primaries as an unfavorable site., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Treatment of extremity rhabdomyosarcomas (RMS) includes chemotherapy, surgery, and radiotherapy. Lymph node irradiation is recommended in the presence of regional node involvement at diagnosis. The aim of this study was to analyze the correlation between the pattern of relapse of non-metastatic extremity RMS and the initial therapies delivered., Methods: All patients with localized extremity RMS prospectively treated in France in the MMT-95 and RMS-05 protocols were selected. Extent of disease and pattern of relapse were evaluated by clinical examination and imaging., Results: We identified 59 patients with clinical characteristics corresponding to unfavorable prognostic factors. Twenty patients (34%) were considered to have lymph node involvement at diagnosis. Regional node biopsy was performed in 32 patients (54%) and modified the lymph node stage in 8 of the 59 patients (14%). Seventy-three percent of patients received radiotherapy. Fifty-two patients achieved first remission. Overall, 26 patients underwent complete tumor resection, 17 had R1 margins, and 5 were not operated due to early tumor progression. With a median follow-up of 82 months (range: 5-287), 18 relapses had occurred, at least locoregional in 12 cases. The 5‑year local and nodal control rates were 73% (63-86%) and 86% (77-95%), respectively. Five-year progression-free and overall survival were 57% (95%CI [45-72%]) and 70% (95%CI [58-84%]), respectively., Conclusion: The main sites of extremity RMS relapse are locoregional. Nodal failures in non-irradiated fields are not uncommon. We recommend systematic biopsy of in-transit nodes, especially in alveolar RMS and/or RMS with regional positive nodes at diagnosis to ensure their negativity., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: p53 plays a key role in the DNA repair process and response to ionising radiation. We sought to determine the clinical phenotype of TP53 mutations and p53 pathway alterations in patients with rhabdomyosarcoma (RMS) and Ewing sarcoma (ES) treated with radiation., Methods: Of patients with available genomic sequencing, we identified 109 patients with RMS and ES treated to a total of 286 radiation sites. We compared irradiated tumour control among tumours with TP53 mutations (n = 40) to those that were TP53 wild-type (n = 246). We additionally compared irradiated tumour control among tumours with any p53 pathway alteration (defined as tumours with TP53 mutations or TP53 wild-type tumours identified to have MDM2/4 amplification and/or CDKN2A/B deletion, n = 78) to those without such alterations (n = 208)., Results: The median follow-up was 26 months from radiation. TP53 mutations were associated with worse irradiated tumour control among the entire cohort (hazard ratio, HR = 2.8, P < 0.0001). Tumours with any p53 pathway alteration also had inferior irradiated tumour control (HR = 2.0, P = 0.003). On multivariable analysis, after controlling for tumour histology, intent of radiation, presence of gross disease, and biologically effective dose, TP53 mutations continued to be associated with a radioresistant phenotype (HR = 7.1, P < 0.0001)., Conclusions: Our results show that TP53 mutations are associated with increased radioresistance in RMS and ES. Novel strategies to overcome this radioresistance are important for improved outcomes in p53 disruptive RMS and ES., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

The aim of this work was to investigate whether Caveolin-1 (Cav-1), a membrane scaffolding protein widely implicated in cancer, may play a role in radiation response in rhabdomyosarcoma (RMS), a pediatric soft tissue tumor. For this purpose, we employed human RD cells in which Cav-1 expression was stably increased via gene transfection. After radiation treatment, we observed that Cav-1 limited cell cycle arrest in the G2/M phase and enhanced resistance to cell senescence and apoptosis via reduction of p21 Cip1/Waf1 , p16 INK4a and Caspase-3 cleavage. After radiotherapy, Cav-1-mediated cell radioresistance was characterized by low accumulation of H2AX foci, as confirmed by Comet assay, marked neutralization of reactive oxygen species (ROS) and enhanced DNA repair via activation of ATM, Ku70/80 complex and DNA-PK. We found that Cav-1-overexpressing RD cells, already under basal conditions, had higher glutathione (GSH) content and greater catalase expression, which conferred protection against acute treatment with hydrogen peroxide. Furthermore, pre-treatment of Cav-1-overexpressing cells with PP2 or LY294002 compounds restored the sensitivity to radiation treatment, indicating a role for Src-kinases and Akt pathways in Cav-1-mediated radioresistance. These findings were confirmed using radioresistant RD and RH30 lines generated by hypofractionated radiotherapy protocol, which showed marked increase of Cav-1, catalase and Akt, and sensitivity to PP2 and LY294002 treatment. In conclusion, these data suggest that concerted activity of Cav-1 and catalase, in cooperation with activation of Src-kinase and Akt pathways, may represent a network of vital mechanisms that allow irradiated RMS cells to evade cell death induced by oxidative stress and DNA damage., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The clinical outcomes for infants with malignant tumors are often worse than older children due to a combination of more biologically aggressive disease in some cases, and increased toxicity-or deintensification of therapies due to concern for toxicity-in others. Especially in infants and very young children, finding the appropriate balance between maximizing treatment efficacy while minimizing toxicity-in particular late side effects-is crucial. We review here the management of malignant tumors in infants and very young children, focusing on central nervous system (CNS) malignancies and rhabdomyosarcoma., (© 2021 Wiley Periodicals LLC.)

Rationale: The best treatment protocol for radiation maculopathy in children has not been determined. The purpose of this study was to determine the effect of photodynamic therapy (PDT) on radiation maculopathy., Patient Concerns: An 11-year-old boy who was originally diagnosed with orbital rhabdomyosarcoma when he was 1 year old, in October 2008. The lesion improved after peripheral blood stem cell transplantation, chemotherapy and radiation therapy. A cataract was detected in his right eye in May 2011, and he underwent cataract surgery in July 2011. Continuous amblyopia training maintained his visual acuity in his right eye. In January 2017, his visual acuity was reduced and macular edema was detected with optical coherence tomography., Diagnoses: We diagnosed radiation maculopathy, from the history of radiation therapy, macular edema by optical coherence tomography, and hyperfluorescent site by fluorescein angiography., Interventions: We performed PDT in June 2017., Outcomes: Treatment with PDT improved macular edema and his visual acuity., Lessons: Radiation retinopathy is progressive disorder with poor prognosis. PDT could be considered to treat radiation maculopathy., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Biliary rhabdomyosarcoma (RMS) is the most common biliary tumor in children. The biliary tract is classified as a favorable primary site. Therefore, patients with localized biliary RMS were included in two consecutive low-risk studies, D9602 and ARST0331, by the Children's Oncology Group (COG). The outcome for these patients treated with low-risk therapy has not been reported., Procedure: Patients with biliary RMS enrolled on COG low-risk trials D9602 or ARST0331 were analyzed. All patients received systemic chemotherapy and those with Group II (microscopic residual) or Group III (macroscopic residual) disease received 36-50.4 Gy adjuvant radiotherapy (RT). Delayed primary excision (DPE) was allowed on both studies., Results: Seventeen patients with biliary RMS were treated on D9602 (n = 7) or ARST0331 (n = 10). Median age was 3.5 years (range 1.7-10.3). Ten (59%) patients had tumors >5 cm and 14 (82%) had Group III disease. Fifteen (88%) patients received RT. The 5-year event-free survival (EFS) and overall survival (OS) were 70.6% (95% confidence interval [CI]: 46.9-94.3%) and 76.5% (95% CI: 54.6-98.4%), respectively. The majority of patients (80%) who received RT did not have disease recurrence while both patients who did not receive RT had local relapse. Five (36%) of 14 patients with Group III disease underwent DPE; two experienced a local relapse. In the nine patients without DPE, two developed local relapse., Conclusions: Patients with localized biliary RMS treated on low-risk studies had suboptimal outcomes. These patients may benefit from therapy on intermediate-risk studies., (© 2021 Wiley Periodicals LLC.)

Purpose: The surgical approach to localized bladder/prostate rhabdomyosarcoma in children may change due to a new radiotherapeutic modality. We assessed the impact of brachytherapy following surgery for local tumor control, and report surgical techniques and outcomes., Materials and Methods: We retrospectively analyzed the records of all children who underwent surgery for bladder/prostate rhabdomyosarcoma, including tumor relapse, at our institution from 2009 onward., Results: A total of 38 patients with a median age of 29 months (range 10 to 134) met inclusion criteria. Five-year overall survival was 92.8% (95% CI 72.9 to 98.1), and event-free survival at a median followup of 12 months (range 3 to 111) was 73.7% (95% CI 53.4 to 86.2). Three treatment groups were defined, ie bladder preserving surgery combined with brachytherapy, bladder preserving surgery alone and cystectomy. Five-year event-free survival rates for the 3 groups were 85.6% (95% CI 61.2 to 95.2), 66.7% (95% CI 27.2 to 88.2) and 50% (95% CI 5.8 to 84.5), respectively. Bladder preserving surgery was performed in 33 patients (87%), of whom 23 (70%) also underwent brachytherapy, while cystectomy was performed in 5 (13%). Reconstructive procedures varied depending on tumor location and spread., Conclusions: Combining brachytherapy with surgery results in a high bladder preservation rate and improves event-free survival compared to surgery alone in children with bladder/prostate rhabdomyosarcoma. The combination is also effective in treating local tumor relapse, and is associated with less extensive reconstructive procedures due to exclusion of tumors of unfavorable size and location for brachytherapy.

Aim: To evaluate the role of radiotherapy (RT) in the treatment of localized primary adult rhabdomyosarcoma (RMS)., Methods: This retrospective study identified 62 consecutive adult patients with localized primary RMS from January 2000 and July 2016. Local failure-free survival (LFFS), distant metastasis-free survival (DMFS) and overall survival (OS) were analyzed by the Kaplan-Meier method. Multivariate Cox proportional hazards regression models were fit to assess the ability of patient characteristics to predict survival., Results: With a median follow-up of 33 months (range, 6-195 months), the 5-year LFFS, DMFS and OS of all patients were 64.0%, 50.0% and 45.0%, respectively. RT was administered to 28 patients (45.2%). Patients who received RT had a higher 5-year LFFS (81.7% vs 47.2%), 5-year DMFS (59.4% vs 43.1%) and 5-year OS (57.1% vs 34.8%) compared with patients who did not received RT. In mulitvariate analysis, RT retained significance as an independent predictor of improved LFFS [hazard ratio (HR) = 0.282; 95% confidence interval (CI), 0.095-0.838; P = 0.023], DMFS (HR = 0.289; 95% CI, 0.125-0.991; P = 0.004) and OS (HR = 0.334; 95% CI, 0.153-0.727; P = 0.006)., Conclusions: RT significantly reduced local recurrence, distant metastasis and tumor mortality compared with no radiotherapy for localized primary adult RMS., (© 2020 John Wiley & Sons Australia, Ltd.)

Background: The purpose of this study is to analyze the influence of radiation therapy on survival in a historical cohort of 56 pediatric patients with head and neck rhabdomyosarcoma., Methods: A historical cohort of 56 pediatric patients with head and neck rhabdomyosarcoma from June 1st, 2013 to June 30th, 2019 was chosen. Clinical data and follow up results were collected including all diagnosis, treatment and prognosis information. Overall survival (OS) and event free survival (EFS) as time-to-event distributions were estimated with Kaplan-Meier method, and univariate analysis was performed with log rank test to detect differences between groups. Multivariate analysis was performed to explore the risk factors for survival with Cox proportional hazard model., Results: The media follow up time of all 56 patients was 31.8 months (range 3.5-74.6 months). There were 26 events during follow up, including 14 disease progressions and 12 relapses. The estimated 5-year OS of all patients was 69.9%, and the estimated 5-year EFS was 48.8%. Patients with radiation therapy as a component of the initial treatment plan had better 5-year OS and EFS compared with those without radiation therapy (OS 80.3% vs. 49.7%, p = 0.003 and EFS 63.9% vs. 21.9%, p < 0.001). In patients with events, those who received salvage radiation therapy had better 5-year OS compared with those who didn't (OS 66.0% vs. 31.2%, p = 0.033). On multivariate analysis, tumor size > 5 cm and non-initial radiation therapy were independent risk factors for OS in all patients, non-initial radiation therapy was an independent risk factor for EFS in all patients, and tumor size > 5 cm was an independent risk factor for OS in patients with events., Conclusions: Radiation therapy as a component of initial treatment can improve the OS and EFS in pediatric head and neck rhabdomyosarcoma patients by enhancing local control, and non-initial radiation therapy is an independent risk factor for OS and EFS. Salvage radiation therapy still can improve OS in patients with disease progression and relapse. Tumor size > 5 cm is an independent risk factor for OS in pediatric HNRMS patients with or without disease progression/relapse.

Purpose: Our purpose was to assess disease outcomes and late toxicities in pediatric patients with rhabdomyosarcoma treated with conformal photon radiation therapy (RT)., Methods and Materials: Sixty-eight patients (median age, 6.9 years) were treated with conformal photon RT to the primary site on a prospective clinical trial. Target volumes included a 1-cm expansion encompassing microscopic disease. Prescribed doses were 36 Gy to this target volume and 50.4 Gy to gross residual disease. Chemotherapy consisted of vincristine/dactinomycin (n = 6), vincristine/dactinomycin/cyclophosphamide (n = 37), or vincristine/dactinomycin/cyclophosphamide-based combinations (n = 25). Patients were evaluated with primary-site magnetic resonance imaging, whole-body [ 18 F]fluorodeoxyglucose positron emission tomography, and chest computed tomography for 5 years after treatment., Results: Five-year disease-free survival was 88% for low-risk (n = 8), 76% for intermediate-risk (n = 37), and 36% for high-risk (n = 23) patients (P ≤ .01 for low risk/intermediate risk vs high risk). The cumulative incidence of local failure (LF) at 5 years for the entire cohort was 10.4%. Tumor size at diagnosis was a significant predictor of LF (P < .01). Patients with head and neck primary tumors (n = 31) had a 35% cumulative incidence of cataracts; the risk correlated with lens dose (P = .0025). Jaw dysfunction was more severe when the pterygoid and masseter muscles received a mean dose of >20 Gy (P = .013). Orbital hypoplasia developed more frequently after a mean bony orbit dose of >30 Gy (P = .041). Late toxicity in patients with genitourinary tumors included microscopic hematuria (9 of 14), bladder-wall thickening (10 of 14), and vaginal stenosis (2 of 5)., Conclusions: Long-term LF rates were low, and higher rates correlated with larger tumors. Treatment-related toxicities resulting in measurable functional deficits were not infrequent, despite the conformal RT approach., (Copyright © 2020 Elsevier Inc. All rights reserved.)